In general, a high power amplifier having a high efficiency (HPA: High Power Amplifier, hereinafter also simply referred to as amplifier) has a low input-output characteristic linearity. Accordingly, if the power is amplified using such an amplifier, a desired output may not be obtained due to distortion of the input-output characteristics. Therefore, in order to compensate the distortion in the amplifier, a digital predistortion circuit has been proposed. This digital predistortion circuit performs digital signal processing on an input signal to the amplifier, to generate an inverse distortion characteristic, which is an inverted characteristic of the distortion characteristic of the amplifier. Then, distortion compensation processing is performed in which the generated inverse distortion characteristic is added to the input to the amplifier, thereby yielding the desired amplifier output (see Non-Patent Literature 1, for example).